The present invention relates to an instrument having a working point which is applied to a surface, and more particularly to a manually manipulated instrument wherein there is a preferred orientation of the working point during the instrument""s use.
Various instruments having a point which is applied to a surface are available on the market. These instruments include, but are not limited to, writing systems, such as fountain pens, ballpoint pens, as well as correction fluid applicators and the like. The writing instruments, as a general rule, comprise a writing tip or point which extends from the barrel containing the ink supply, the instrument being held in the hand of the user during the writing process. In most of these writing instruments, particularly ballpoint pens, the writing tips are known to function more effectively if retained in a perpendicular position relative to the surface being written on. However, in most instances the writing instrument is not applied vertically during the writing process, but is inclined to the writing surface by the user at an angle which is generally in the vicinity of 60xc2x0 to the writing surface.
In the case of a ballpoint pen, typically applied to the writing surface at about a 60xc2x0 angle, the rim surrounding the ball may contact the writing surface and interfere with the smooth operation of the ball. A danger also exists that application at a 60xc2x0 angle may provide wear to the ball to the extent that the ball becomes loosened.
In view of the above, it has been proposed that the point or ball-carrying portion of the ballpoint pen be oriented such that it extends at an angle to the axis of the writing instrument barrel to compensate for the tilting of the barrel during the writing process. A pen which is typical of this type of instrument is shown and described in U.S. Pat. No. 5,012,663, issued to Robert L. Brown and assigned to the assignee of the present invention.
It has, however, been found that in employing a pen of the type described above, wherein the point is disposed at an angle with the barrel longitudinal axis, orientation of the point is often difficult and may result in a poor quality of writing being produced. If the point is not oriented such that it lies at right angles to the writing surface, the user will have to reorient the writing instrument, or writing will proceed on the rim of the point.
It is, therefore, an object of the present invention to provide a writing instrument wherein the point extends at an angle to the longitudinal axis of the barrel wherein proper orientation of the point to the writing surface is ensured.
Another object of the invention is to provide a writing instrument of the type set forth above which provides proper orientation of the point to the writing surface prior to the start of the writing process.
A further of the invention is to provide a writing instrument of the type set forth above wherein the proper orientation of the point to a writing surface is retained during the writing process.
Another object of the invention is to provide a writing instrument of the above type wherein the point is rotatable relative to the barrel but remains fixed relative to the barrel during the writing process.
Yet another object of the invention is to provide a writing instrument of the type set forth above which is simple in construction and easily manufactured.
The aforementioned objects and other objectives which will become apparent as the description proceeds are accomplished by providing a manually manipulated instrument comprising an elongated tubular barrel member having a longitudinal axis. A working point for application to a surface is at the forward end of the barrel, and the point is mounted for rotation and axial movement relative to the barrel longitudinal axis. A gripping structure is disposed between the working point and the tubular barrel, along the longitudinal axis, for impeding rotation of the working point with the working point in its rearwardmost position.
In a more detailed sense, the instrument may be a writing instrument having an elongated tubular barrel member with a longitudinal axis and a writing point mounted on one end of the barrel. The point may be disposed at an angle with respect to the barrel longitudinal axis and mounted for rotation about the longitudinal axis. The writing instrument may be in the form of a ballpoint pen, in which instance the point comprises a writing ball.
The longitudinal axis is generally disposed at the centerline of the elongated tubular barrel and the instrument may further include an elongated member mounted for rotation in the elongated tubular barrel, in which case the point is fixed to the elongated member for rotation with the member.
Both the tubular barrel and the elongated member are preferably cylindrical in shape, and the elongated member may comprise an ink cartridge when the writing instrument is a pen.
In one embodiment of the writing instrument the elongated member comprises a weight portion disposed on the elongated member on the opposite side of the longitudinal axis from that of the point.
In an alternate embodiment, a writing instrument has an elongated barrel member, a writing point mounted at the forward end of the barrel, the point being disposed at an angle with respect to the barrel longitudinal axis and is mounted for free rotation about and axial movement along the barrel longitudinal axis, relative to the barrel. A gripping structure is disposed between the barrel and the writing point along the longitudinal axis for impeding rotation of the writing point when the writing point is in its rearwardmost position along the longitudinal axis.
The gripping structure generally comprises a rearwardly facing shoulder on the elongated member on which the point is fixed, and a forwardly facing surface on the elongated barrel, the surfaces being in spaced relation, one with the other, when the writing point is disposed at a forward location along the longitudinal axis, and in contact one with the other when the writing point is disposed at a rearward position along the longitudinal axis. At least one of the surfaces is of a frictional material and may be located either adjacent the forward end of the writing instrument or adjacent the rearward end of the writing instrument. The frictional material is generally disposed on the elongated barrel and may be in the form of an O-ring of resilient frictional material.